Q146876: PRB: DAO Error 3028 When Creating a DAO Workspace

Article: Q146876
Product(s): Microsoft C Compiler
Version(s): 4.0 4.1 4.2 5.0 6.0
Operating System(s): 
Keyword(s): kbcode kbDAOsearch kbDatabase kbMFC kbVC kbVC400 kbVC410 kbVC420 kbVC500 kbVC600
Last Modified: 30-JUL-2001

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The information in this article applies to:

- The Microsoft Foundation Classes (MFC), included with:
   - Microsoft Visual C++, 32-bit Editions, version 4.0 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 5.0 
   - Microsoft Visual C++, 32-bit Professional Edition, version 5.0 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 6.0 
   - Microsoft Visual C++, 32-bit Professional Edition, version 6.0 
   - Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
- The DAO SDK, included with:
   - Microsoft Visual C++, 32-bit Editions, versions 4.0, 4.1 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 4.2 
   - Microsoft Visual C++, 32-bit Professional Edition, version 4.2 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 5.0 
   - Microsoft Visual C++, 32-bit Professional Edition, version 5.0 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 6.0 
   - Microsoft Visual C++, 32-bit Professional Edition, version 6.0 
   - Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
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SYMPTOMS
========

The following DAO error 3028 may occur when you try to create a workspace DAO
object:

  Can't start application. The system database is missing or opened
  exclusively by another user.

CAUSE
=====

This error can occur if you have failed to specify a system database or have
assigned the system database after performing operations with the database
engine.

RESOLUTION
==========

It is important that the SystemDB property of the database engine be set prior
to performing any operations with the database engine. If you are using the
dbDAO C++ classes included with the DAO SDK, you can set the system database by
using code similar to this code:

     // get database engine object but don't fill its collections
     CdbDBEngine eng(FALSE, FALSE);

     // set the system database
     eng.SetSystemDB(_T("d:\\work\\sectest.mdw"));

     // Finish initializing the engine object
     eng.Start();

     CdbWorkspace wsp;

     // The following function call will generate the 3028
     // error if a System Database hasn't been assigned or if the
     // second argument of the constructor for CdbDBEngine didn't
     // receive FALSE.

     wsp= eng.CreateWorkspace(_T("Test"),_T("MyUserName"),
                              _T("MyPassword"));

Or, alternately, use the CdbDBEngine::SetInitPath() method before opening or
creating a CdbWorkspace object.

If you are using the MFC DAO classes, use code similar to this code:

     //Initialize global MFC DAO engine
     AfxDaoInit( );
     DAODBEngine* pDBEngine = AfxDaoGetEngine( );

     // Set up system database
     COleVariant var( _T("d:\\work\\sectest.mdw"), VT_BSTRT );
     // NOTE: put_SystemDB was a late addition to DAO
     // and is not yet wrapped by MFC
     DAO_CHECK( pDBEngine->put_SystemDB( var.bstrVal ) );

     CDaoWorkspace wsp;
     wsp.Create(_T("Test"),_T("MyUserName"), _T("MyPassword"));

Or, alternately, use the CDaoWorkspace::SetInitPath() method before opening or
creating a CDaoWorkspace object.

STATUS
======

This behavior is by design.

======================================================================
Keywords          : kbcode kbDAOsearch kbDatabase kbMFC kbVC kbVC400 kbVC410 kbVC420 kbVC500 kbVC600 
Technology        : kbAudDeveloper kbMFC
Version           : 4.0 4.1 4.2 5.0 6.0
Issue type        : kbprb

=============================================================================

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